Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

An anti-reflective coating material, a microelectronic structure that
includes an anti-reflective coating layer formed from the anti-reflective
coating material and a related method for exposing a resist layer located
over a substrate while using the anti-reflective coating layer provide
for attenuation of secondary reflected vertical alignment beam radiation
when aligning the substrate including the resist layer located thereover.
Such enhanced vertical alignment provides for improved dimensional
integrity of a patterned resist layer formed from the resist layer, as
well as additional target layers that may be fabricated while using the
resist layer as a mask.

Claims:

1. A method for exposing a resist layer comprising: forming layered over
a substrate a target layer, an anti-reflective layer located over the
target layer and a resist layer also located over the target layer to
form a layered substrate, the anti-reflective coating layer including a
composition of matter that exhibits a first absorption peak corresponding
with an exposure apparatus vertical alignment beam wavelength; vertically
aligning the layered substrate within an exposure apparatus while using
an exposure apparatus vertical alignment beam and horizontally aligning
the layered substrate within the exposure apparatus while using an
exposure apparatus horizontal alignment beam to yield an aligned layered
substrate; and exposing the resist layer within the aligned layered
substrate within the exposure apparatus while using an exposure beam.

2. The method of claim 1 further comprising: developing the resist layer
to form a patterned resist layer; and treating the target layer while
using the patterned resist layer as a mask.

3. The method of claim 1 wherein the first absorption peak is in a range
greater than about 800 nanometers.

4. The method of claim 3 wherein: the composition of matter exhibits a
second absorption peak corresponding with an exposure wavelength; and the
exposure wavelength is less than about 300 nanometers.

5. The method of claim 4 wherein the composition of matter does not
exhibit a third absorption peak interposed between the first absorption
peak and the second absorption peak.

6. The method of claim 1 wherein the anti-reflective coating layer is
interposed between the resist layer and the target layer.

7. The method of claim 1 wherein the resist layer is interposed between
the anti-reflective coating layer and the target layer.

8. A method for exposing a resist layer comprising: positioning within an
exposure apparatus a microelectronic structure that includes a reflective
layer located over a substrate and a resist layer located over the
reflective layer; vertically aligning the microelectronic structure
within the exposure apparatus while attenuating a reflection of a
vertical alignment beam from the reflective layer, to provide an aligned
substrate; and exposing the aligned substrate within the exposure
apparatus.

[0005] The process of fabricating a semiconductor structure within a
semiconductor substrate, or another type of microelectronic structure
within another type of microelectronic substrate, typically includes the
use of a resist layer, that is selectively exposed and subsequently
developed while using an exposure apparatus and then a development
apparatus, to form a patterned resist layer that is used as a mask layer
for selectively forming a particular semiconductor structure or a
particular microelectronic structure within and upon the semiconductor
substrate or the microelectronic substrate.

[0006] While the use of resist layers and exposure apparatus is thus quite
common within the semiconductor and microelectronic fabrication art, the
use of resist layers and exposure apparatus is nonetheless not entirely
without problems within the semiconductor and microelectronic fabrication
art. In particular, a proper exposure of a substrate having a resist
layer located thereover within an exposure apparatus may often be
compromised by spurious light effects. In addition, such compromised
exposure in turn may lead to unacceptable resist features, such as
improperly sized contact holes, that are formed from such compromised
exposure of a blanket resist layer.

[0007] Various microelectronic structures, and related structures such as
lithographic structures, for which optical considerations are relevant,
are known in the microelectronic fabrication and generally related arts.

[0008] For example, van der Werf et al., in U.S. Pat. No. 4,568,140,
teaches an optical component that may be used in an optical fiber
telecommunications system, where the optical component includes an
anti-reflective coating effective in the infrared region. The
anti-reflective coating includes a number of stacked uniform layers
having appropriately graduated indexes of refraction.

[0009] In addition, Miller et al., in U.S. Pat. No. 6,136,719, teaches a
method for etching a portion of a thickness of a resist layer from over a
substrate that is employed for fabricating a semiconductor structure. The
method uses an infrared absorbing material that is incorporated within
the resist layer, where an infrared absorption intensity of the infrared
absorbing material provides a measurement of a thickness of the resist
layer when etching the resist layer.

[0010] Further, Zheng et al., in U.S. Pat. No. 6,579,662, teaches an
imaging member, such as a negative working printing plate, that may be
thermally imaged absent conventional alkaline processing. To achieve the
foregoing result, the imaging member uses an infrared absorbing dye.

[0011] Still further, Williams et al., in U.S. Pat. No. 6,689,518 teaches
an imaging element, such as a photographic display imaging element, that
may incorporate an invisible marking. Such an invisible marking may be
effected using an infrared absorbing dye.

[0012] Still yet further, Weed et al., in U.S. Pat. No. 6,861,201, teaches
particular photopolymer compositions that are optically sensitive in the
infrared region. The particular photopolymer compositions include an
infrared absorbing dye that is compatible with a hexaarylbiimidazole
(HABI) photoinitiator.

[0013] Finally, Tao et al., in U.S. Pat. No. 7,175,949, teaches a negative
working radiation sensitive composition that may be used within an
imaging element. The negative working radiation sensitive composition
includes a polymer backbone that incorporates a carbazole derivative.

[0014] Lithographic methods, lithographic materials and lithographic
apparatus are certain to remain useful as semiconductor and
microelectronic fabrication technology advances. To that end, desirable
are lithographic methods, lithographic materials and lithographic
apparatus that have enhanced performance.

SUMMARY

[0015] The invention includes: (1) an anti-reflective coating material;
(2) a microelectronic structure that includes an anti-reflective coating
layer that comprises the anti-reflective coating material; and (3) a
method for exposing a resist layer within the microelectronic structure
that includes the anti-reflective coating layer that comprises the
anti-reflective coating material. The anti-reflective coating material
has a first absorption peak (i.e., having a first absorbance greater than
about 0.4) corresponding with an exposure apparatus vertical alignment
beam wavelength (i.e., greater than about 800 nanometers and typically
from about 900 to about 1200 nanometers). The anti-reflective coating
material may also have a second absorption peak (i.e., having a second
absorbance from about 0.1 to about 0.7) corresponding with an exposure
beam wavelength (i.e., less than about 300 nanometers and typically 193
nanometers). Finally, the anti-reflective coating material typically also
has no additional absorption peak interposed between the first absorption
peak and the second absorption park (i.e., an absorbance less than about
0.1 interposed between the first absorption peak and the second
absorption peak).

[0016] The microelectronic structure and the method for exposing the
resist layer while using the anti-reflective coating composition
generally provides that the anti-reflective coating composition is
located (i.e., in the form of an anti-reflective coating layer)
interposed between a target layer and a resist layer located and
successively layered and formed over a substrate. However, the invention
also contemplates a microelectronic structure and related method that
includes the resist layer located interposed between the target layer and
an anti-reflective coating layer comprised of the anti-reflective coating
material, where the anti-reflective coating layer is furthest from the
substrate. The substrate including the resist layer is vertically aligned
(for focusing purposes) and horizontally aligned (for registration
purposes) prior to exposing the resist layer while using a resist
exposure beam. The presence of the anti-reflective coating layer, whether
located interposed between the target layer and the resist layer or
whether located above the resist layer which may in-turn be located above
the target layer and finally the substrate, attenuates reflections from a
reflective layer that also underlies the resist layer when vertically
aligning the substrate having the resist layer thereover prior to
exposing the resist layer.

[0017] The invention is predicated upon the observation that absent an
anti-reflective coating layer in accordance with the invention, a
vertical alignment of a substrate having a resist layer located there
over may not be accurate since a vertical alignment beam (i.e., that is
also intended as an auto focus alignment beam that typically has a
wavelength in the near infrared) which is typically a small angle
reflected alignment beam, may be influenced by reflections from the
underlying reflective layer.

[0018] A particular anti-reflective coating material in accordance with
the invention includes a composition of matter that exhibits a first
absorption peak in a wavelength range greater than about 800 nanometers.
The first absorption peak corresponds with an exposure apparatus vertical
alignment beam wavelength.

[0019] A particular microelectronic structure in accordance with the
invention includes a substrate, as well as a resist layer located over
the substrate. This particular microelectronic structure also includes an
anti-reflective coating layer also located over the substrate. The
anti-reflective coating layer includes a composition of matter that
exhibits a first absorption peak at an exposure apparatus vertical
alignment beam wavelength.

[0020] A particular method for exposing a resist layer includes forming,
layered over a substrate, a target layer, an anti-reflective coating
layer located over the target layer and a resist layer also located over
the target layer, to form a layered substrate. The anti-reflective
coating layer includes a composition of matter that exhibits a first
absorption peak at an exposure apparatus vertical alignment beam
wavelength. The method also includes vertically aligning the layered
substrate within an exposure apparatus while using an exposure apparatus
vertical alignment beam and horizontally aligning the layered structure
within the exposure apparatus while using an exposure apparatus
horizontal alignment beam to yield an aligned layered substrate. The
method also includes exposing the resist layer within the aligned layered
substrate within the exposure apparatus while using an exposure beam.

[0021] Another particular method for exposing a resist layer in accordance
with the invention includes positioning within an exposure apparatus a
microelectronic structure that includes a reflective layer located over a
substrate and a resist layer located over the reflective layer. The
method also includes vertically aligning the microelectronic structure
within the exposure apparatus while attenuating a reflection of a
vertical alignment beam from the reflective layer, to provide an aligned
substrate. The method also includes exposing the aligned substrate within
the exposure apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The objects, features and advantages of the invention are
understood within the context of the Description of the Preferred
Embodiment, as set forth below. The Description of the Preferred
Embodiment is understood within the context of the accompanying drawings,
that form a material part of this disclosure, wherein:

[0023]FIG. 1 shows a schematic diagram of a microelectronic substrate
juxtaposed a reticle within an exposure apparatus generally in accordance
with the microelectronic fabrication art.

[0024]FIG. 2 shows a schematic diagram illustrating the results of
vertically aligning the microelectronic substrate including overlying
layers and a resist layer located thereover while using selected
components within the exposure apparatus whose schematic diagram is
illustrated in FIG. 1.

[0025]FIG. 3 shows an ideal absorption spectrum of an anti-reflective
coating material and an anti-reflective coating layer in accordance with
the invention.

[0026]FIG. 4 shows an absorption spectrum of a commercially available
near infrared absorbing dye.

[0027]FIG. 5 to FIG. 11 show a series of schematic cross-sectional
diagrams illustrating the results of progressive stages in forming a
patterned layer within a microelectronic structure while using an
anti-reflective coating layer to enhance focus when exposing a resist
layer used for forming the patterned layer in accordance with a
particular embodiment of the invention.

[0028]FIG. 12 to FIG. 18 show a series of schematic cross-sectional
diagrams illustrating the results of progressive stages in forming a
patterned layer within a microelectronic structure while using an
anti-reflective coating layer to enhance focus when exposing a resist
layer used for forming the patterned layer in accordance with another
particular embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0029] The invention, which includes an anti-reflective coating material,
a microelectronic structure that includes an anti-reflective coating
layer comprising the anti-reflective coating material and a method for
exposing a resist layer and forming a patterned layer within the
microelectronic structure that includes the anti-reflective coating layer
that comprises the anti-reflective coating material, is understood within
the context of the description set forth below. The description set forth
below is understood within the context of the drawings described above.
Since the drawings are intended for illustrative purposes, the drawings
are not necessarily drawn to scale.

[0030]FIG. 1 shows a schematic diagram of an exposure apparatus (i.e., a
photoexposure apparatus such as a photolithographic exposure apparatus)
illustrating the relative positioning of a vertical alignment beam, a
horizontal alignment beam and an exposure beam with respect to a reticle
and a substrate.

[0031] Specifically, FIG. 1 shows a substrate 10 that includes therein an
alignment mark 11 located within the substrate 10. FIG. 1 also shows a
reticle 14 located juxtaposed the substrate 10 that includes the
alignment mark 11. As is understood by a person skilled in the art, it is
desirable to position the substrate 10 at a proper distance both
vertically (i.e., for focusing purposes) and horizontally (i.e., for
registration purposes) with respect to the reticle 14 so that a properly
focused and registered image is latently formed within a resist layer
(i.e., not shown) that is located and formed upon or over the substrate
10.

[0032] To provide for such a proper vertical positioning of the substrate
10 within the exposure apparatus of FIG. 1, the particular exposure
apparatus whose schematic diagram is illustrated in FIG. 1 uses an
incident vertical alignment beam 12b that emanates from a vertical
alignment beam source 12a. Absent a resist layer located over the
substrate 10, the incident vertical alignment beam 12b impinges upon the
substrate 10 and is reflected from the substrate 10 as a reflected
vertical alignment beam 12c that is received by a vertical alignment beam
detector 12d. Such an incident vertical alignment beam 12b and reflected
vertical alignment beam 12c may also conventionally be known as an
incident auto-focus beam and a reflected auto-focus beam.

[0033] In order to provide for such a proper horizontal positioning of at
least the reticle 14 with respect to the substrate 10 within the exposure
apparatus whose schematic diagram is illustrated in FIG. 1, the
particular exposure apparatus whose schematic diagram is illustrated in
FIG. 1 uses a horizontal alignment beam 16 that passes through a
designated transparent portion of the reticle 14 and aligns with respect
to the alignment mark 11 that is located within the substrate 10. At
least one of the reticle 14 and the substrate 10 is positioned
horizontally with respect to the other of the reticle 14 and the
substrate 10 so that the horizontal alignment beam 16 is optimally
positioned with respect to the desired transparent portion of the reticle
14 and the alignment mark 11.

[0034] Subsequent to aligning at least the reticle 14 (and possibly also
other related exposure beam optical components) vertically and
horizontally with respect to the substrate 10, an exposure beam 18 is
made to impinge upon the reticle 14 is a fashion to selectively expose
portions of a resist layer (which again is not shown) otherwise located
over the substrate 10.

[0035]FIG. 2 shows in greater detail the results of vertically aligning
the substrate 10 that is illustrated in FIG. 1 within the exposure
apparatus that is illustrated in FIG. 1, but wherein the substrate 10 now
has additional layers located thereupon and/or thereover. As is
illustrated within the schematic diagram of FIG. 2, the additional layers
located upon or over the substrate 10 are intended in-part as a
reflective layer 20 located upon the substrate 10. Also included is a
transparent layer 22 located upon exposed portions of the substrate 10
and the reflective layer 20. Finally, also included is a resist layer 24
located upon the transparent layer 22. The substrate 10 may also have
additional layers of other material types located and formed thereover,
although this particular embodiment illustrates the reflective layer 20
and the transparent layer 22.

[0036] As is intended within the schematic diagram of FIG. 2, and as will
be described in greater detail below, the resist layer 24 and the
transparent layer 22 may comprise resist materials and transparent
materials that are both otherwise generally transparent to a wavelength
of light that comprises the incident vertical alignment beam 12b. Thus,
as is further illustrated within the schematic cross-sectional diagram of
FIG. 2, at an appropriate angle of incidence with respect to the surface
of the resist layer 24, the incident vertical alignment beam 12b splits
at the surface of the resist layer 24 to a reflected vertical alignment
beam 12c and a secondary incident vertical alignment beam 12b'. This
particular secondary incident vertical alignment beam 12b' is in turn
reflected from the reflective layer 20 underlying the resist layer 24 to
provide a secondary reflected vertical alignment beam 12c'.

[0037] As is further illustrated within the schematic diagram of FIG. 2,
the reflected vertical alignment beam 12c and the secondary reflected
vertical alignment beam 12c' both may potentially converge at the
vertical alignment beam detector 12d. As a result of this possible
convergence, a vertical alignment error may be introduced into a
photoexposure apparatus as is generally illustrated in FIG. 1, so that
the resist layer 24 that is located over the substrate 10 is not located
in an optimal focal plane for exposing the resist layer 24. As a further
result of such a vertical alignment error, the resist layer 24 may be
improperly exposed and thus eventually provide a patterned resist layer
of dimensional constraints and integrity other than originally intended.
Such a patterned resist layer of dimensional constraints and integrity
other than originally intended is undesirable since the dimensional
constraints and integrity other than originally intended in turn provide
for microelectronic layers and structures of dimensional constraints and
integrity other than originally intended.

[0038] In order to address the foregoing vertical misalignment of the
microelectronic substrate 10 including in particular the resist layer 24
that is illustrated in FIG. 2 within an exposure apparatus as is
illustrated in FIG. 1 and in-part within FIG. 2, the invention provides
in general for use of a particular type of anti-reflective coating layer
(i.e., comprising a particular type of anti-reflective coating material).
In a particular embodiment that follows, the particular anti-reflective
coating layer is illustrated as interposed between the resist layer 24
and the substrate 10, and also between the resist layer 24 and the
reflective layer 20. In another particular embodiment that follows, the
particular anti-reflective coating layer is illustrated as located above
the resist layer 24 that in-turn is located above the substrate 10 and
the reflective layer 20. In a broad embodiment, such an anti-reflective
coating layer comprises an anti-reflective coating material that
attenuates reflection via absorption (with an extinction coefficient
greater than about 0.4) at a vertical alignment beam wavelength (which
will typically be in a near infrared wavelength region greater than about
800 nanometers and preferably from about 900 to about 1200 nanometers).
In a less broad, but nonetheless desirable operative embodiment such an
anti-reflective coating layer comprises an anti-reflective coating
material that attenuates reflection via absorption (with a extinction
coefficient greater than about 0.4) at a vertical alignment beam
wavelength (which will typically be in a near infrared wavelength region
greater than about 800 nanometers and preferably from about 800 to about
1200 nanometers) and attenuates reflection via absorption (with an
extinction coefficient from about 0.1 to about 0.7) at an exposure
radiation wavelength (which will typically be less than 300 nanometers
and more preferably from about 150 to about 300 nanometers and most
preferably 193 nanometers), while transmitting (absent an absorption
peak, and with an extinction coefficient less than about 0.1) at a
horizontal alignment beam wavelength (which will typically be in a
visible range from about 400 to about 700 nanometers).

[0039]FIG. 3 shows a general spectrum of a typical anti-reflective
coating material or a typical anti-reflective coating layer in accordance
with the foregoing optical absorption characteristics. As is illustrated
in FIG. 3, such an anti-reflective coating material or an anti-reflective
coating layer is illustrated as possessing: (1) at reference numeral 31
an extinction coefficient (k) of about 0.1 to about 0.7 (i.e., more
particularly about 0.3) at an exposure wavelength of 193 nanometers; (2)
at reference numeral 32 an extinction coefficient of zero at a horizontal
alignment beam wavelength, such as 630 nanometers, and/or an overlay
measurement beam wavelength, such as 500 nanometers; and (3) at reference
numeral 33 an extinction coefficient of greater than about 0.4 (i.e.,
more particularly about 1.0) at a vertical alignment beam wavelength,
such as 1000 nanometers.

[0040] Desirably, when located above a resist layer which in-turn is
located above a reflective layer and a substrate, an anti-reflective
material or an anti-reflective coating in accordance with such a
particular embodiment may alternatively possess, as also correlating with
FIG. 3: (1) at reference numeral 31 an extinction coefficient of about 0
at an exposure wavelength of 193 nanometers; (2) at reference numeral 32
an extinction coefficient of zero at a horizontal alignment beam
wavelength, such as 630 nanometers, and/or an overlay measurement beam
wavelength, such as 500 nanometers; and (3) at reference numeral 33 an
extinction coefficient greater than about 0.4 at a vertical alignment
beam wavelength, such as 1000 nanometers.

[0041]FIG. 4 shows a spectrum of a commercially available dye that
fulfills the optical properties that are illustrated within the
absorption spectrum of FIG. 3. This particular commercially available dye
is available from H. W. Sands Corporation, Jupiter, Fla. 33477, as
product number SDA4137. Other commercially available infrared absorbing
dyes are also readily available.

[0042] For example, additional examples of infrared absorptive dyes that
may be used within the context of the invention are taught within Cuny,
in U.S. Pat. No. 5,723,617. Cuny, the teachings of which are incorporated
herein fully by reference, teaches isoquinoline dyes that absorb in the
near infrared in a wavelength range from about 700 to about 1400 nm,
absent an absorption peak in the 300 to 400 nanometer region.

[0043] Either the dye whose spectrum is illustrated in FIG. 4, or the
additional dyes that are taught within Cuny, or alternatively any of
several other commercially available dyes, may be used in conjunction
with an otherwise appropriately transparent base polymer material, to
form an anti-reflective coating material (i.e., a composition of matter).
A desired thickness of an anti-reflective coating layer formed from the
anti-reflective coating material will generally guide a loading of a dye
within the otherwise appropriately transparent base polymer material.
Thus, operative compositions of matter for an anti-reflective coating
material in accordance with the invention may be readily determined
absent undue experimentation.

[0044]FIG. 5 to FIG. 11 show a series of schematic diagrams illustrating
the results of successive stages in aligning a substrate having a resist
layer located thereover and exposing the resist layer located over the
substrate while using an anti-reflective coating layer comprising an
anti-reflective coating material in accordance with a particular
embodiment of the invention. This particular embodiment of the invention
comprises a first embodiment of the invention.

[0045]FIG. 5 first shows the substrate 10. The reflective layer 20 is
located upon the substrate 10. The transparent layer 22 is located upon
exposed portions of the reflective layer 20 and the substrate 10. An
anti-reflective coating layer 23 in accordance with the invention is
located upon the transparent layer 22. The resist layer 24 is located
upon the anti-reflective coating layer 23.

[0047] When the substrate 10 in particular comprises a semiconductor
substrate material, the substrate 10 may include microelectronic devices,
such as in particular semiconductor devices, located and formed therein
and/or thereupon, that are otherwise generally conventional in the
semiconductor fabrication art. Such semiconductor devices may include,
but are not necessarily limited to, resistors, transistors, diodes and
capacitors.

[0048] The alignment mark 11 within the substrate 10 may comprise any of
several geometric shapes that are either recessed within the substrate 10
or layered upon the substrate 10. Circles, squares, regular and irregular
polyhedra as geometric shapes may each be used within the context of the
alignment mark 11, absent limitation to the embodiment or the invention.

[0049] The reflective layer 20 may comprise any of several reflective
materials that are reflective with respect to a wavelength of light that
is used within an exposure apparatus vertical alignment beam 12b that is
illustrated in FIG. 1 and FIG. 2. Such reflective materials may include,
but are not necessarily limited to, reflective conductor materials,
reflective semiconductor materials and reflective dielectric materials.
Reflective conductor materials are particularly common, and to that end
such reflective conductor materials may include, but are not necessarily
limited to metals, metal alloys, metal nitrides and metal silicides that
are otherwise generally conventional in the microelectronic fabrication
art. Particularly common are copper and copper alloy conductor materials
that are appropriately reflective. Such reflective materials may be
formed using methods including but not limited to plating methods,
chemical vapor deposition methods and physical vapor deposition methods
that provide the reflective layer 20 of a generally conventional
thickness.

[0050] The transparent layer 22 may comprise any of several materials that
are transparent with respect to the wavelength of the photoexposure
apparatus incident vertical alignment beam 12b that is illustrated in
FIG. 1 and FIG. 2. Such transparent materials may include, but are not
necessarily limited to, oxides, nitrides and oxynitrides of silicon,
although oxides, nitrides and oxynitrides of other elements are not
excluded. Such transparent materials may also be formed using methods
that are generally conventional in the microelectronic fabrication art.
Non-limiting examples include chemical vapor deposition methods and
physical vapor deposition methods that provide the transparent layer 22
of a generally conventional thickness.

[0051] As is understood by a person skilled in the art, the transparent
layer 22 is intended as a target layer within the context of the instant
embodiment and the invention. While the instant embodiment illustrates
such a target layer as generally comprising a transparent dielectric
material, within the embodiments in particular or the invention in
general, a target layer may comprise transparent, semi-transparent or
opaque materials that may comprise, but are not necessarily limited to
conductor materials, semiconductor materials or dielectric materials.

[0052] The anti-reflective coating layer 23 comprises an anti-reflective
material having optical absorption properties within the context of
specific wavelength regions that are described above. Such an
anti-reflective coating layer 23 may comprise a single layer or an
aggregate of layers that provide the above described absorption
properties in the corresponding wavelength regions that are described
above.

[0053] For example, the dye whose optical spectrum is illustrated in FIG.
4 may, due to the bimodal absorption characteristics of that dye, be
employed by itself, in conjunction with an otherwise transparent carrier
and binder, to form an anti-reflective coating material (i.e., a
composition of material) or an anti-reflective coating layer.
Alternatively, a first layer of a bilayer or multi-layer anti-reflective
coating layer may comprise an absorptive material with absorbance
characteristics in the 800 to 1200 nanometer range while a second layer
of a bilayer anti-reflective coating layer may comprise an absorptive
material with absorbance characteristics in the less than 300 nanometer
range.

[0054] Similarly, while the above disclosure is directed towards an
anti-reflective coating layer that comprises an infrared absorptive dye,
which is typically an organic material, neither the embodiment nor the
invention is intended to be so limited. Rather, the embodiment and the
invention also contemplate that particular anti-reflective coating layers
in accordance with the invention may comprise purely organic materials,
purely inorganic materials or composites of inorganic materials and
organic materials.

[0055] The resist layer 24 may comprise any of several resist materials
formed to thicknesses that are otherwise generally conventional in the
microelectronic fabrication art. Under certain circumstances, the resist
material may also contain an infrared absorptive material such as an
infrared absorptive dye. Thus, under those circumstances, the
anti-reflective coating layer 22 and the resist layer 24 may be merged
into a single layer. Non-limiting examples include positive resist
materials, negative resist materials and hybrid resist materials that
possess properties of positive resist materials and negative resist
materials. For illustrative purposes within the context of further
aligning, exposing and developing of the substrate 10 and/or the resist
layer 24 located thereover in accordance with the instant embodiment, the
resist layer 24 as illustrated will implicitly be intended as comprising
a positive resist material, although neither the embodiment nor the
invention is intended to be so limited.

[0056]FIG. 5 also illustrates the vertical alignment beam source 12a and
the vertical alignment beam detector 12d that are illustrated in FIG. 1
and FIG. 2. Both the vertical alignment beam source 12a and the vertical
alignment beam detector 12d are otherwise generally conventional in the
microelectronic resist layer exposure apparatus art. The vertical
alignment beam source 12a is intended as an infrared source, generally in
a wavelength range from about 800 to about 1200 nanometers. The vertical
alignment beam detector 12d is intended as an appropriate detector for
detecting radiation from the vertical alignment beam source 12a. Solid
state detectors are common, but by no means limit the invention.

[0057]FIG. 5 finally shows the reticle 14 that is also illustrated in
FIG. 1. The reticle 14 comprises a transparent substrate 14a having
located thereupon a patterned opaque material layer 14b. The transparent
substrate 14a may comprise any of several transparent materials.
Non-limiting examples include glasses, such as but not limited to
silicate glasses, as well as quartz materials. The patterned opaque
material layer 14b may comprise any of several opaque materials, which
are typically metal opaque materials and most commonly chromium metal
opaque materials. Typically, the transparent substrate 14a has a
conventional thickness, and the patterned opaque material layer 14b also
has a conventional thickness.

[0058]FIG. 6 shows the results of vertically aligning the substrate 10
including in particular the resist layer 24, as is illustrated in FIG. 5,
with respect to the reticle 14.

[0059] As is illustrated in FIG. 6, the incident vertical alignment beam
12b emanates from the vertical alignment beam source 12a and impinges
upon the resist layer 24 where the incident vertical alignment beam 12b
is primarily reflected as the reflected vertical alignment beam 12c. In
concert with the schematic diagram of FIG. 2, a secondary incident
vertical alignment beam 12b' splits from the incident vertical alignment
beam 12b at the surface of the resist layer 24. However, due to the
presence of the anti-reflective coating layer 23, and thus in
contradistinction with the schematic diagram of FIG. 2, the secondary
incident vertical alignment beam 12b' does not reach the reflective layer
20, and for that reason there is no secondary reflected vertical
alignment beam that correlates with the secondary reflected vertical
alignment beam 12c' that is illustrated in FIG. 2. Absent such a
secondary reflected vertical alignment beam, the substrate 10 including
the resist layer 24, may be more precisely vertically aligned than the
substrate 10 that includes the resist layer 24 but absent an
anti-reflective coating layer, that is illustrated in FIG. 2.

[0060]FIG. 7 shows the results of horizontally aligning the substrate 10
with respect to the reticle 14. Such a horizontal alignment uses the
horizontal alignment beam 16 for positioning the reticle 14 with respect
to the alignment mark 11 within the substrate 10. Such positioning is
effected incident to a horizontal movement of at least one of the reticle
14 and the substrate 10 with respect to the other of the reticle 14 and
the substrate 10.

[0061]FIG. 8 shows the results of exposing the resist layer 24 with an
exposure radiation beam 18 to form an exposed resist layer 24', while
using the reticle 14 and exposure optics (that are not otherwise shown)
that are properly vertically and horizontally positioned with respect to
the resist layer 24 and the substrate 10.

[0062]FIG. 9 shows a resist layer 24'' that may be developed from the
resist layer 24' that is illustrated in FIG. 8. The resist layer 24''
that is illustrated in FIG. 9 may be developed from the resist layer 24'
that is illustrated in FIG. 8 while using a resist developer that is
otherwise generally conventional in the microelectronic fabrication art,
and appropriate to the resist material which comprises the resist layer
24'.

[0063]FIG. 10 shows the results of etching the anti-reflective coating
layer 23 and the transparent layer 22 to form an anti-reflective coating
layer 23' and a transparent layer 22' while using the resist layer 24''
as a mask. The foregoing etching is typically effected while using a
plasma etch method that provides generally straight sidewalls to the
anti-reflective coating layer 23' and the transparent layer 22'. Such a
plasma etch method will typically use an etchant gas composition that is
appropriate to the materials that comprise the anti-reflective coating
layer 23 and the transparent layer 22.

[0064]FIG. 11 shows the results of stripping the resist layer 24'' and
the anti-reflective coating layer 23' from the microelectronic structure
of FIG. 10. The resist layer 24'' and the anti-reflective coating layer
23' may be stripped using methods and materials that are also generally
conventional in the semiconductor fabrication art. Included in general
are wet chemical stripping methods and materials, and dry plasma
stripping methods and materials, as well as combinations of those methods
and materials.

[0065]FIG. 11 shows a microelectronic structure fabricated in accordance
with a first embodiment of a method of the invention that uses an
anti-reflective coating layer that comprises an anti-reflective coating
material in accordance with the invention. The microelectronic structure
of FIG. 11 includes a transparent layer 22' with enhanced dimensional
control. The enhanced dimensional control results from an improved
vertical alignment (i.e., focusing) of an exposure apparatus when
exposing a resist layer that is used as a mask when etching the
transparent layer 22' from a corresponding blanket transparent layer. The
improved vertical alignment is understood within the context of a
vertical alignment beam, and in particular within the context of
attenuation of secondary reflections of the vertical alignment beam from
an underlying reflective layer beneath the anti-reflective coating layer
which is located beneath the resist layer when vertically aligning and
subsequently exposing the resist layer.

[0066]FIG. 12 to FIG. 18 show a series of schematic cross-sectional
diagrams illustrating the results of progressive stages in aligning a
substrate having a resist layer located thereover and exposing the resist
layer located over the substrate while using an anti-reflective coating
layer comprising an anti-reflective coating material in accordance with
another particular embodiment of the invention. This other particular
embodiment of the invention comprises a second embodiment of the
invention.

[0067]FIG. 12 shows the substrate 10 including the alignment mark 11. The
reflective layer 20 is located upon the substrate 10. The transparent
layer 22 is located upon exposed portions of the reflective layer 20 and
the substrate 10. A resist layer 24 is located upon the transparent layer
22. An anti-reflective coating layer 25 in accordance with the invention
is located upon the resist layer 24. Thus, this second embodiment differs
from the first embodiment with respect to a reverse vertical ordering of
the resist layer 24 and an anti-reflective coating layer 23 or 25.

[0068] Within this second embodiment, the anti-reflective coating layer 25
comprises an anti-reflective material including a composition of matter
that exhibits a first absorption peak at an exposure apparatus vertical
alignment beam wavelength, as is further discussed above within the
context of FIG. 1 to FIG. 4.

[0069] Similarly with the first embodiment as illustrated within FIG. 5 to
FIG. 11, further processing of the microelectronic structure of FIG. 12
includes: (1) vertically aligning the layered microelectronic substrate
10 within an exposure apparatus while using an exposure apparatus
vertical alignment beam and horizontally aligning the layered
microelectronic substrate 10 within the exposure apparatus while using an
exposure apparatus horizontal alignment beam, to yield an aligned layered
substrate 10 and (2) exposing the resist layer 24 within the aligned
layered substrate 10 within the exposure apparatus while using an
exposure beam that is not specifically illustrated in FIG. 12.

[0070] The anti-reflective coating layer 25 within the second embodiment
may comprise materials, have dimensions and be formed using methods that
are analogous, equivalent or identical to the materials, dimensions and
methods used for forming the anti-reflective coating layer 23 that is
used within the first embodiment. In particular the anti-reflective
coating layer 25 comprises an absorptive material with absorbance
characteristics analogous, equivalent or identical to the absorbance
characteristics of the anti-reflective coating layer 23 illustrated
within the first embodiment.

[0071]FIG. 13 shows the results of vertically aligning the substrate 10
including in particular the resist layer 24, as is illustrated in FIG.
12, with respect to the reticle 14.

[0072] As is illustrated in FIG. 13, and similarly with the schematic
diagram of FIG. 2, a secondary incident vertical alignment beam 12b'
splits from the incident vertical alignment beam 12b at the surface of
the anti-reflective coating layer 25. However, due to the presence of the
anti-reflective layer 25, and thus in contradistinction with the
schematic diagram of FIG. 2, the secondary incident vertical alignment
beam 12b' does not appreciably reach the resist layer 24 or the
reflective layer 20, and for this reason there is no secondary reflected
vertical alignment beam that correlates with the secondary reflected
vertical alignment beam 12c' that is illustrated in FIG. 2. Absent such a
secondary reflected vertical alignment beam, the substrate 10, including
the resist layer 24, may be more precisely vertically aligned than the
substrate 10 that includes the resist layer 24 but absent an
anti-reflective coating layer, that is illustrated in FIG. 2.

[0073]FIG. 14 shows the results of horizontally aligning the substrate 10
with respect to at least the reticle 14 while using the horizontal
alignment beam 16. FIG. 14 within this particular second embodiment
correlates and corresponds with FIG. 7 within the first embodiment.

[0074]FIG. 15 shows the results of exposing the resist layer 24 with the
exposure radiation beam 18 to form an exposed resist layer 24', while
using the reticle 14 and exposure optics (that are not otherwise shown)
that are properly vertically and horizontally positioned with respect to
the resist layer 24 and the substrate 10.

[0075]FIG. 16 first shows the results of completely removing the
anti-reflective coating layer 25 from the microelectronic structure of
FIG. 15. FIG. 16 also shows a resist layer 24'' that may be developed
from the resist layer 24' that is illustrated in FIG. 15. The
anti-reflective layer 25 may be completely removed and stripped from the
microelectronic structure of FIG. 15 to provide in-part the
microelectronic structure that is illustrated in FIG. 16 while using
methods and materials that effectively selectively strip the
anti-reflective coating layer 25 while leaving the resist layer 24'.
Appropriately selective etchants, such as but not limited to wet chemical
etchants, dry plasma etchants and combinations of wet chemical etchants
and dry plasma etchants, may be used.

[0076] Subsequent to, or simultaneous with, stripping the anti-reflective
coating layer 25, the resist layer 24'' that is illustrated in FIG. 16
may be developed from the resist layer 24' that is illustrated in FIG. 15
while using a resist developer that is otherwise generally conventional
in the microelectronic fabrication art, and appropriate to the resist
material which comprises the resist layer 24 or 24'.

[0077]FIG. 17 shows the results of etching the transparent layer 22 to
form a transparent layer 22' while using the resist layer 24'' as a mask.
The foregoing etching is typically effected while using a plasma etch
method that provides generally straight sidewalls to the transparent
layer 22'. Such a plasma etch method will typically use an etchant gas
composition that is appropriate to the material that comprises the
transparent layer 22.

[0078]FIG. 18 shows the results of stripping the resist layer 24'' from
the microelectronic structure of FIG. 17. The resist layer 24'' may be
stripped using methods and materials that are also generally conventional
in the microelectronic fabrication art. Included in general are wet
chemical stripping methods and materials, and dry plasma stripping
methods and materials.

[0079]FIG. 18 shows a microelectronic structure fabricated in accordance
with an additional embodiment of a method of the invention that uses an
anti-reflective coating layer that comprises an anti-reflective coating
material in accordance with the invention. The microelectronic structure
of FIG. 18 includes a transparent layer 22' with enhanced dimensional
control. The enhanced dimensional control results from an improved
vertical alignment (i.e., focusing) of an exposure apparatus when
exposing a resist layer that is used as a mask when etching the
transparent layer 22' from a corresponding blanket transparent layer. The
improved vertical alignment is understood within the context of a
vertical alignment beam, and in particular within the context of
attenuation of a secondary reflection of the vertical alignment beam from
an underlying reflective layer 20 beneath the anti-reflective coating
layer which is located above the resist layer which in turn is located
above the reflective layer 20, when vertically aligning and subsequently
exposing the resist layer.

[0080] The preferred embodiments are illustrative of the invention rather
than limiting of the invention. Revisions and modifications may be made
to methods, materials, structures and dimensions of a microelectronic
structure illustrated in accordance with the preferred embodiments, while
still providing an anti-reflective coating material, a microelectronic
structure that includes an anti-reflective layer that includes the anti
reflective coating material and a method for exposing a resist layer and
subsequently forming a patterned layer while using the microelectronic
structure that includes the anti-reflective coating layer that includes
the anti-reflective coating material, while still providing particular
materials, structures and methods in accordance with the invention,
further in accordance with the accompanying claims.